Thyroid Gland Lecture Notes

Front 1

Your thyroid gland has an important role in your body's metabolism

Back 1

True

Front 2

Thyroid disease is relatively rare

Back 2

False

Front 3

People with hyperthyroidism often feel as if "their motor is always running."

Back 3

True

Front 4

In hypothyroidism, your thyroid gland produces sufficient thyroid hormnone and your metabolic rate falls.

Back 4

True

Front 5

Thyroid disease develops rapidly with a sudden onset of symptoms

Back 5

False

Front 6

Delayed diagnosis of thyroid disease is unimportant for long-term health

Back 6

False

Front 7

Thyroid disease can be diagnosed with a blood test

Back 7

True

Front 8

Thyroid screening is not recommended, and just increases medical costs.

Back 8

False

Front 9

A goiter means that you have an overactive thyroid.

Back 9

False

Front 10

A thyroid nodule usually is not cancerous

Back 10

True

Front 11

Thyroid Physiology

Back 11

*Thyroid releases 2 hormones
-T3
-T4

Front 12

Thyroid Physiology

Back 12

*Complex negative feedback system

Front 13

Health Promotion/Maintenance Thryroid

Back 13

*Normal thyroid function=Euthyroid
-Hormones
*Stimulation of energy use
*Stimulation of the heart
*Necessary for normal growth and development

Front 14

Thyroid Disorders - Goiter

Back 14

*Enlargement of thyroid unrelated to inflamm. or neoplasm

Front 15

Thyroid Disorders - Hypothyroidism

Back 15

*Deficiency of thyroid hormone (T3&T4)

Front 16

Thyroid Disorders - Hyperthyroidism

Back 16

*Excessive thyroid hormone production (T3&T4)
-Iodine needs to be available for the thyroid to make T3&T4

Front 17

Goiters

Back 17

*Simple nontoxic goiter - hyperplasia of the thyroid gland in response to inability of gland to secrete enough hormone to meet metabolic needs
*Nodular - multiple nodules usually women > 40
*Toxic Nodular Goiter - associated with signs of hyperthyroidism

Front 18

Hyperthyroidism (Thyrotoxicosis)

Back 18

*Sustained increased synthesis and release of thyroid hormones by the thyroid gland - thyrotoxicosis
*2 Major Causes
-Graves' Disease Most Common
*Usually occurs in womrn 4-10 times more often than men, 30-50 years old
-Toxic nodular goiter (Plummer's Disease), same S&S except no exophthalmos, result of adenoma
-impaired venous damage exophthalmos can be permanent
*Severe hyperthyroidism (Thyroid Storm = Thyroid Crisis)

Front 19

Hyperthyroidism - Other causes (Graves' Disease is most common)

Back 19

*Over-treatment of hypothyroidism
*Thyroid Cancer
*Thyroiditis
*Pituitary or hypothalamus disease
*Post-partum thyroiditis

Front 20

Graves' Disease (Most Common)

Back 20

*Autoimmune of unknown etiology
*Hyperthyroidism & hyperplasia caused by antibodies
*Antibodies called thyroid stimulating antibodies (TSAbs)- act like TSH
*Increased hormone cause
-increased metabolism (measure HR)
-increased sensitivity (to stress) to stimulation by ANS (symptom)

Front 21

Clinical Manifestations

Back 21

*Early
-Nervousness
-Hand tremors at rest
-Increased appetite with weight loss
*Elderly
-May only have apathy, anorexia, and confusion

Front 22

Clinical Manifestations
*Later (Untreated symptoms)

Back 22

-Chaotic emotional state, fine muscle and tongue tremors
-Loose stools, diarrhea, increased BS
-Increased T,P,R,BP, increased CO, atrial dysrrhythmias
-Exothalmos
-Change in menstrual cycle, decreased libido in men
-Hard, nonpitting (orange peel like), pretibial and ankle edema

Front 23

Complications

Back 23

*Thyroid Storm or Crisis - acute, rare, severe hypermetabolic state

Front 24

Thyroid Storm = Thyroid Crisis

Back 24

*Causes=infection, surgery (develops post-operatively), trauma with preexisting hyperthyroidism
*S&S = tachycardia, heart failure, arrhythmias, hyperthermia, restlessness, agitation, N/V, coma (many effects, refer to Lewis)
*Hyperthermia - metabolism is increases
*Effects every organ in the body

Front 25

Diagnosis of Hyperthyroidism (Primary)

Back 25

*S&S
*Lab - increased T3, T4, FT4, low TSH
*EKG - tachycardia, a-fib or change in P&T waves (heart is overworking)
*RAIU - increased radioactive iodine update (test that evaluates function of thyroid gland)

Front 26

Thyroid/Parathyroid Studies:T4

Back 26

Measures total serum level of T4. Useful in evaluating thyroid function and monitoring thyroid therapy. Normal values are 5-12ug/dl

Front 27

Thyroid/Parathyroid Studies:T3

Back 27

Measures serum levels of T3. It is helpful in diagnosing hyperthyroidism if T4 levels are normal. Normal values are 65-195 ng/dl
Nursing Responsibility: Same as for T4

Front 28

Thyroid/Parathyroid Studies:T3 resin uptake (T3RU)

Back 28

This study indirectly measures binding capacity of thyroid-binding globulin. Normal values are 25-35% (0.25-0.35).
Nursing Responsibility: Same as for T4

Front 29

Thyroid/Parathyroid Studies:Free T4

Back 29

Measures active component of total T4. Normal values are 1.0-3.5 ng/dl
Nursing Responsibility: Same as for T4

Front 30

Thyroid/Parathyroid Studies:Free T3

Back 30

Measures active component of total T3. Normal values are 0.26-0.65 ng/dl
Nursing Responsibility: Same as for T4

Front 31

Thyroid/Parathyroid Studies: Thyroid 131I uptake (radioactive iodine uptake

Back 31

Provides direct measure of thyroid activity. Useful for evaluation of functional activity of solitary thyroid nodules. Small tracer dose of 131I is given orally or intravenously. Serum uptake measurements are drawn at 2 to 4 and at 24 hours. Normal serum values for 2-4 hours are 3-10%; for 24 hours, they are 5-30%. Values are affected by drugs, seafood, certain radiographic contrast media, and antiseptics containing iodine.
Nursing Responsibility: Instruct patient to discontinue thyroid medication and start T3 (Cytomel) 2-3 times/day for 4 weeks. Tell patient to report for further testing in 10-14 days. Collect 24-hour urine specimen.

Front 32

Thyroid/Parathyroid Studies: Thyroid-stimulating hormone (TSH)

Back 32

This test measures level of TSH, which is markedly elevated in primary hypothyroidism. Normal values are 0.3-5.4 uU/ml.
Nursing Responsibility: Inform patient that fasting is not necessary. Inform patient that blood sample will be drawn. Observe venipuncture site for bleeding or hematoma formation.

Front 33

Thyroid/Parathyroid Studies: Calcitonin

Back 33

High calcitonin level with normal serum calcium level is associated with medullary thyroid carcinoma.
Nursing Responsibility: Ensure that patient has fasted. Inform patient that blood sample will be drawn. Observe venipuncture site for bleeding or hematoma formation.

Front 34

Radiologic Studies: Thyroid scan

Back 34

Used to evaluate nodules of the thyroid. Tracer dose of technetium is given intravenously. Scanner passes over thyroid and makes graphic record of radiation emitted. Normal thyroid scan reveals homogenous pattern with symmetric lobes.
Nursing Responsibility: Determine whether other tests requiring iodine preparation (IV pyelogram, saturated solution of potassium iodine, or barium enema) have been done within 30 days (can invalidate test). Explain procedure to patient.

Front 35

Parathyroid Studies Serum Studies: Parathyroid hormone (PTH)

Back 35

Measures PTH level in serum. Normal range depends on assay used (check with laboratory). This study must be interpreted in terms of concomitantly drawn serum calcium level.
Nursing Responsibility: Fasting specimen preferred. Inform patient that blood sample will be drawn. Sample must be kept on ice. Observe venipuncture site for bleeding or hematoma formation.

Front 36

Parathyroid Studies Serum Studies: Total serum calcium

Back 36

Measures total serum calcium to help detect bone and parathyroid disorders. Hypercalcemia can indicate primary hyperparathyroidism, and hypocalcemia can indicate hypoparathyroidism.
Nursing Responsibility: Fasting specimen preferred. Inform patient that blood sample will be drawn. Observe venipuncture site for bleeding or hematoma formation. Ensure that prolonged tourniquet application does not cause falsely elevated values. Adjust total calcium for albumin levels. Using following formula: Total serum calcium (mg/dl) - Albumin (g/dl) + 4.0 = Adjusted total serum calcium.

Front 37

Parathyroid Studies Serum Studies: Phosphorus

Back 37

Measures inorganic phosphorus. Hyperphosphatemia indicates primary hypoparathyroidism or secondary causes (e.g., renal failure); hypophosphatemia indicates hyperparathyroidism. Phosphorus and calcium levels are inversely related.
Nursing Responsibility: Needs for fasting varies with lab. Determine fasting requirement. Inform patient that blood sample will be drawn. Observe venipuncture site for bleeding or hematoma formation.

Front 38

The nurse is assessing for endocrine dysfunction. Which manifestations are most common?

Back 38

a. Goiter and alopecia
b. Exophthalmus and tremors
c. Fatigue and depression
d. Polyuria and polyphagia
Answer: c. Fatigue and depression

Front 39

Treatment options

Back 39

*First treat symptoms
*Surgery
*Anti-thyroid drugs
*Radioactive Iodine or brachytherapy (radiation preferred for adults in U.S.)
*Adjunctive medications

Front 40

Treatment: Hyperthyroidism (suppress secretion of TH)

Back 40

*Treat S&S
-tachycardia, arrhythmias
-tremors
-fever
*Reduce circulating thyroid hormone with meds
*Anti-thyroid drugs for 6 months to 2 years
-Propylthiouracil (PTU)
-Saturated solution of Potassium Iodide (SSKI)
-Methimazole (Tapazole)
disadvantage=noncompliance & recurrence. Use for young Graves, pre-op, pre-radiation See handout

Front 41

**Treatment of choice**
Radioactive Iodine (131I)

Back 41

*Rx of chooice for nonpregnant adults
*Causes destruction of Thyroid tissue
*Maximal effect=2-3 months --
*high incidence of post rx hypothyroidism
-See Lehne may require 2nd dose in 6-8 weeks, simple & noninvasive
BRACHYTHERAPY - inpatient, higher dose, outpatient=precautions (Time, Distance, Shielding)

Front 42

**Treatment of choice**
Radioactive Iodine (131I)

Back 42

Outpatient=precautions
-Teach pts to go home on precautions
-Flush toilet 2x etc.

Front 43

Treatment
*Surgical removal of Thyroid Tissue
--Used when

Back 43

*In combination with radiation
*Unresponsive to anti-thyroid medication
*Not a candidate for RAI (pregnant woman or child)
*Malignancy
*Large goiter w/compression of trachea
--Most rapid decrease in T3 and T4

Front 44

Thyroid Surgery

Back 44

*Pre-op Teaching
*Post-op
-Assess for respiratory obstruction, edema (q 2hrs. for 24 hrs.)
-Assess for laryngeal nerve damage
-Assess for hemorrhage (check behind neck)
-Assess for signs of hypocalcemia r/t removal or damage to parathyroids
-Semi-fowlers postion, avoid flexion of the neck

Front 45

Thyroid Surgery: Adjunctive therapies

Back 45

-propranolol, verapamil, corticosteroids, and nonradioactive iodine (Lugol's solution, SSKI)
-Nutritional=4000-5000kcal/day
High metabolic rate burning calories
See handout

Front 46

Nursing Process

Back 46

**See Care Plan**

Front 47

Hyperthyroidism

Back 47

-Intolerance to heat
-Fine-straight hair
-Bulging eyes
-Facial flushing
-Enlarged thyroid
-Tachycardia
-Increased systolic B/P
-Breast enlargement
-Weight loss
-Muscle wasting
-Localized edema
-Menstrual changes (Amenorrhea)
-Increased diarrhea
-Tremors
-Finger clubbing

Front 48

The nurse's best response when asked about Grave's disease is:
a. It is thought to be genetic and cause is unknown
b. It is associated with Iodine deficiency and a decrease in hormone
c. Antibodies develop and destroy thyroid tissue causing a decrease in hormone
d. Antibodies form in genetically susceptible people and stimulate overproduction of hormone

Back 48

Correct Answer:
d. Antibodies form in genetically susceptable people and stimulate overproduction of hormone

Front 49

Hypothyroidism

Back 49

*Primary - resulting from destruction of thyroid tissue or defective hormone syn.
*Secondary r/t pituitary disease w/ decreased TSH secretion or hypothalamic problems w/ decreased TRH secretion
*Tertiary - hypothalamus fails to produce TRH

Front 50

Incidence

Back 50

*Infancy=cretinism 1 in 3700 births in US
-Usually maternal iodine deprivation or thyroid abnormality
*Adults most common medical disorder in US - affects 8% women & 2% men over 50
-called hypothyroidism or severe=myxedema
-More frequent in females, usually over 50 but any age/sex

Front 51

Etiology

Back 51

*Adults (in US where iodine is adequate)
-Hashimotos Thyroiditis - auto immune destroys thyroid gland
-Graves Disease - auto immune destroys thyroid gland
-Surgical removal of thyroid or pituitary/Radiation damage
-Nutritional/Medicinal goitrogens (food or meds that contain thyroid inhibiting substances)
-Treatment for hyperthyroidism (131I)
Iodine deficiency most common world-wide

Front 52

Pathophysiology

Back 52

*Decreased levels of thyroid hormone lead to slowing metabolic rate involving all body processes
*Decreased O2 consumption and metabolism (decreased HR and temperature)

Front 53

Clinical Manifestations: Hypothyroidism

Back 53

*Cardiovascular - bradycardia, weakened contractility, cardimyopathy, CAD
*Cerebral - diminished blood flow=mental sluggishness, memory loss, lethargy, change in mood, etc.
*GI - decreased motility, achlorhydria (no HCL), constipatiion
*Reproductive - infertility

Front 54

Clinical Manifestations: Hypothyroidism

Back 54

*Impaired wound healing (slow metabolism)
*Sensitivity to cold
*Weight gain
*dry, waxy non-pitting edema
*Dry skin and hair (cellular metabolism
*Depression
Mild disease may be asymptomatic
If left untreated cerebral hypoxia and decreased metabolism may lead to stupor - Myxedema Coma

Front 55

Myxedema Coma (severe hypothyroidism)

Back 55

*Precipitated by infection, drugs, cold or trauma
*Rare medical emergency
-Hypoventilation
-Hypothermia
-Hypotension
Support life functions (airway,breathing,circulation), IV thyroid hormone

Front 56

Signs and Symptoms of Hypothyroidism

Back 56

-Dry hair/thin
-Brittle/dry skin
-Increased susceptibility to infection
-Increased sensitivity to CNS depressants
-Bradycardia
-Decreased tendon reflex response
-Constipation
-Weight gain, Obese
-Forgetful, lethargic
-Decreased sweat
-Fatigue, apathy
-Puffy, edematous

Front 57

Diagnosis: Hypothyroidism

Back 57

*Symptoms (mimic normal aging signs)
*Serum TSH - determines cause (high=defect in thyroid, low=defect in pituitary or hypothalamus then inject TRH if TSH increase suggest Hypothalamus
*T3, T4, T3RU = low, sometimes normal in elderly
*Decreased RAIU (Know all about RAIU for exam)

Front 58

Medical Management: Hypothyroidism

Back 58

*Lifelong Thyroid Hormone Replacement
-Levothyroxine (Synthroid, Levothroid)-synthetic preparation identical to the natural occurring hormone T4-Drug of choice
-Liothyroonine (Cytomel, Triostat) - synthetic preparation identical to the natural occurring hormone-T3-acts quicker, shorter duration and much more expensive (Myxedema Coma) see client instructions

Front 59

Preoperative instructions for a client undergoing a subtotal thyroidectomy include:
a. Support of the head when turning
b. Avoid coughing post-op
c. Immobilize head and neck for incision healing
d. Tingling of lips and fingers is expected

Back 59

Answer:
a. Support of the head when turning

Front 60

Signs and Symptoms of Hypothyroidism

Back 60

-Intolerance to cold
-Receding hairline
-Facial and Eyelid Edema
-Dull-Blank Expression
-Extreme fatigue
-Thick tongue-slow speech
-Anorexia
-Brittle nails and hair
-Menstrual disturbances
-Constipation
-Muscle aches and weakness
-Dry skin (coarse and scaly)
-Lethargy
-Apathy
-Hair loss

Front 61

Late Clinical Manifestations: Hypothyroidism

Back 61

-Subnormal temp
-Bradycardia
-Weight gain
-Decreased LOC
-Thickened skin
-Cardiac complications